To let you know my intent in this response as well as my inflictions, I am not flying off the handle and irrately typing this. I calmly and flatly have to say that your husband's attitude is completely unacceptable.
While it is true that may be how he feels, it sounds like he is unwilling to try any possible means to change it, or consider any possible reason why he has reached this point. It sounds like he expects you to just accept that he is desiring other women and himself more than his life mate.
I don't know what you look like or what your style is but if you haven't tried it yet: get a new hair style (one you like but one that's different from the one you've had the past 5, 10, 15 years) buy some new clothes, try wearing makeup, jewelry. It sounds like you're outdoorsy type people and where I come from those type of people (myself included) spend significantly less energy on their looks.
Look into a skin care regime or even procedure to freshen up your look and help you look younger, revived, etc. You have a responsibility to your husband to look your best and keep yourself up, even if it means wearing nicer clothes that you wouldn't usually wear, wearing a little more makeup, doing your hair a little more often (this is all from personal experience. This has been like a two year shift for me and i'm still in the early stages of learning to make myself look more than presentable).
Don't approach this as a desperate attempt to catch his eye. You attitude in this should be out of respect for his needs (a woman who makes an effort to look good for him) and for yourself (i'm still learning this one). You really do feel better about yourself when you put some effort into this, even if you don't think you feel bad about yourself right now (although it sounds like you may). Someone told me once, when you feel your worst is when you should make the most effort to look your best.
Your husband has a responsibility to you as his wife to make an effort to try to please you. *sex is not about his need (or lack of it) for pleasure*
you both exist in this relationship and make an effort in it. Sex is not an exception. He needs to make an effort to please you and take care of you. That alone should be a turn on for him and something he desires. If not, he's got some rocky roads ahead in these mid to later years in your marriage. *it's not all about him*. You are in this together to meet each others needs in every area. It sounds like he just doesn't care to even make an effort. Maybe he's afraid of something? If I were you I would not let him get away with this. I'm not talking about nagging him until he responds just to get you to leave him alone. I'm talking about challenging his attitude, helping him realize that while he may not feel like he has the need any more you do, and as your husband he has a responsibility and should desire to please you and take care of your needs.
He obviously does have a desire for this but is using other outlets, which is totally inappropriate in a relationship where you have out and out committed yourselves to each other...If you didn't want that type of committment, why did you get married?
Anyway, I would ask him to sit with you and talk through it and be open abuot what he's feeling. Help him talk it through and find out why it seems like he doesn't even care to find out why he doesn't desire you any more, and hopefully that will lead to finding out what's missing and you can work through it together towards a deeper relationship based on serving each other and meeting each others' needs.
